The factors in this dialog determine how TPC displays distances and directions. You can choose from the grid, ground and geodetic options available for your edition of the program. See Survey Distance and Direction.
The Distance Type and Direction Type you select in this dialog become the defaut types for this survey. Until you choose an alternate type, TPC will use these default types for Traverses, Drawings and COGO.
So lets say you are doing a public lands survey. You would do the following:
That's it. TPC now thinks like you do, in geodetic ground distance at the specified project elevation and true bearings or azimuths. Pretty simple.
In the pulldown lists for Distance and Direction, TPC adds 'PLSS" to the options prescribed in the Bureau of Land Management, Manual of Survey Instruction.
Enter a mapping angle correction you want to keep track for this project. In any Direction Type pulldown, like the one in this dialog, select the 'True Bearing/Azimuth (project mapping angle x°xx'x")'. The mapping angle you enter here will appear in this list and be available anywhere you can choose a direction type.
Enter a combined factor for this project. You can now select 'Ground Distance (combined factor x.xxxxxxx)' from the any Distance Type pulldown.
The Combined Factor relates ground distances to grid distances using the following equation: Ground Distance x Combined Factor = Grid Distance.
Think of this as the combined factor for the project. It is a combination of the project's grid factor and elevation factor.
Enter a project elevation. You can now select the 'Ground Distance (project elevation x,xxx.xx)' from any Distance Type pulldown.
Choose the Distance and Direction types you want to use as the defaults for this survey.
Select OK to accept the changes you have made and return to the previous view.
Select Cancel to return to the previous view without making any changes.